2009MNRAS.399.1175C

We present consistent modelling of line and continuum infrared (IR) spectra in the region close to the Galactic Centre. The models account for the coupled effect of shocks and photoionization from an external source. The results show that the shock velocities range between ∼65 and 80km/s and the pre-shock densities between 1/cm3 in the interstellar medium (ISM) to 200/cm3 in the filamentary structures. The pre-shock magnetic field increases from 5x10^–6G in the surrounding ISM to ∼8x10^–5G in the arched filaments. The stellar temperatures are ∼38000K in the Quintuplet cluster and ∼27000K in the Arches Cluster. The ionization parameter is relatively low (<0.01) with the highest values near the clusters, reaching a maximum >0.01 near the Arches Cluster. Depletion from the gaseous phase of Si is found throughout the whole observed region, indicating the presence of silicate dust. Grains including iron are concentrated throughout the arched filaments. The modelling of the continuum spectral energy distribution in the IR range indicates that a component of dust at temperatures of ∼100-200K is present in the central region of the Galaxy. Radio emission appears to be thermal bremsstrahlung in the E2-W1 filaments crossing strip; however, a synchrotron component is not excluded. More data are necessary to resolve these questions.